Answer:
Option 2nd is correct

Explanation:
The nth term for the arithmetic sequence is given by:

where,
is the first term
d is the common difference
n is the number of terms.
As per the statement:
From the given graph:
At n =1

At n =4

Using the nth term formula for the arithmetic sequence:

Substitute the given values we have;

Subtract 4 from both sides we have;

Divide both sides by 3 we have;

or

Therefore, the common difference for the given sequence as shown is,
